1. Field of the Invention
The invention relates to novel melamine resins modified with a mixture of polyalkylene glycol and an alkylated methylomelamine, paper sheets impregnated therewith and decorative laminates prepared therefrom and methods of making the same.
2. Description of the Related Art
Conventional high pressure decorative laminates are produced by heat and pressure consolidating a laminate assembly comprising, in superimposed relationship, a plurality (e.g., 2-9) of phenol/formaldehyde resin impregnated saturating kraft paper sheets, a melamine/formaldehyde resin impregnated decor sheet and, optionally, a melamine/formaldehyde resin impregnated overlay sheet in a multi-opening press at from about 120.degree.14 250.degree. C. and 6.9 MPa-11.0 MPa. The laminate assemblies are pressed, in back-to-back relationship, with the aid of release sheets and press plates, such that from about 8-35 laminates can be produced from each press opening during each press cycle.
Recently, there has been introduced decorative laminates which are produced on low pressure, i.e., 0.7 MPa to 1.7 MPa, continuous laminating machines. These laminates are prepared by continuously subjecting rolls of superimposed papers to heat and pressure consolidation in a double-belt press, see U.S. Pat. No. 4,473,613, hereby incorporated herein by reference.
High pressure, i.e., 3.4 MPa to 5.2 MPA, continuous production is currently being actively investigated by many laminate producers, whereby an increased number of kraft paper core sheets may be employed so as to prepare laminates whose thickness is substantially equivalent to those laminates produced for many years via the use of multi-openings presses.
The conventional laminates produced by multi-openings presses are normally from about 0.5-10 mm in thickness whereas the continuous laminates are normally from about 0.2-1.3 mm in thickness.
While the conventional laminates have found astounding success as decorative surfaces for counter-tops, furniture, wall panels, etc., and the future is seen to be bright for low pressure, continuously produced laminates for the same and other service applications, the need is still present for the improvement of these laminates, especially in the area of radial crack resistance and surface resistance to boiling water.